1. Field of the Invention
The present invention discloses a sense amplifier circuit, and more particularly a sense amplifier circuit and a method of operation of a sense amplifier to be used for sensing low power signals for integrated circuits.
2. Description of the Prior Art
Non-volatile memory includes a plurality of memory cells. The non-volatile memory may have a sense amplifier as one of the elements in the non-volatile memory. The sense amplifier is an analogue circuit that is a part of the read circuitry which is used for reading data in the non-volatile memory. The sense amplifier may be used to sense the low power signals from a bit line which represents a data bit (1 or 0) stored in a memory cell, and amplify the small voltage swing to recognizable logic levels so the data can be interpreted properly by logic outside the memory.
The data bit (1 or 0) of a memory cell is differentiated by comparing cell current of a memory cell to a reference current. For logic 1 data bit, value of the cell current is greater than the value of the reference current. For logic 0 data bit, value of the cell current is lower than the reference current. Typically, the cell current for logic 0 data bit is set at zero amperes.
An increased number of programming cycles affects the value of the cell current of the memory cell. AS the number of programming cycles increase, the value of the cell current changes to value that is closer to the reference current. When the value of the cell current and the reference current is close enough, the sense amplifier would not be able to accurately compare the cell current and the reference current, thus, error occurs.